function AD_showHideCombo(which) {
	var target = which.parentNode.getElementsByTagName("span")[0].getElementsByTagName("div")[0];
	target.id = "tempComboId";
	if (target.style.display == "block") {
		target.style.display = "none";
	}
	else {
		target.style.display = "block";
		AD_listenForClicks();
	}
}
function AD_listenForClicks() {
	document.body.onclick = function() { alert("Hi"); };
}



<div class="ADlistBox">
	<h6 onmouseup="AD_showHideCombo(this);">list header</h6>
    <span>
    	<div>
            <ul>
                <li><a href="#">list item 1</a></li>
                <li><a href="#">list item 2</a></li>
                <li><a href="#">list item 1</a></li>
                <li><a href="#">list item 2</a></li>
                <li><a href="#">list item 1</a></li>
                <li><a href="#">list item 2</a></li>
                <li><a href="#">list item 1</a></li>
                <li><a href="#">list item 2</a></li>
                <li><a href="#">list item 2</a></li>
                <li><a href="#">list item 1</a></li>
                <li><a href="#">list item 2</a></li>
                <li><a href="#">list item 1</a></li>
                <li><a href="#">list item 2</a></li>
            </ul>
	</div>
</span>
</div>